Abstract

In this paper, a new surfactant–polymer enhanced oil recovery (EOR) system is investigated for the feasibility of injection in Dagang. The newSP ï¬‚ooding system has been designed and developed for Dagang oilfield with Dagang petroleum sulfonate (SLPS) as the primary ingredient. The dynamic behavior of the system and the interactions of the system components have been investigated through various methods, including dissipative particle dynamics (DPD) molecular modeling technology and dynamic interfacial-tension analysis. The results have shown a significant synergistic effect between sulfonate and nonionic surfactant. The interfacial tension (IFT) and its time to reach equilibrium could be dramatically decreased, suggesting a fast diffusion–adsorption characteristic of ionic surfactants as well as the high surface activity of nonionic surfactants. The SP ï¬‚ooding formulation was optimized. A pilot test has been carried out. The ï¬eld trial provides useful information for the further large-scale application of the SP system in Dagang oilfield.

Key words: Surfactant-polymer flooding, sulfonate, interfacial tension, dynamic behavior, pilot field trial.